Question

which macronutrient do we use second for energy?
carbohydrates
proteins
fats

Explanation:

Carbohydrates are the body's primary energy - source. Fats are used as an energy reserve and are the second - choice for energy when carbohydrates are depleted. Proteins are mainly for building and repairing tissues and are not the second - choice for energy under normal circumstances.

Answer:

Fats